If, in an internal combustion engine, air enters into the fuel line and there, in particular into the injectors, considerable problems occur when the internal combustion engine is restarted. This is the case, for example, when the driver of the vehicle does not fill the tank in a timely manner and the fuel in the tank has been fully depleted, and the fuel pumping system aspires air which penetrates into the high-pressure zone. Such aspiration of air usually results in the internal combustion engine stalling immediately. The air may be easily removed from the lines, the pump, and the reservoir such as the rail, by de-aerating. If the air reaches the injectors, the injectors are much more difficult to de-aerate.
In particular in the case of injectors containing a hydraulic coupler, air penetration and the subsequent restart of the internal combustion engine are problematic.
It is known that such aspiration of air and the problem condition caused thereby may be avoided by shutting off the internal combustion engine in a timely manner. This means that the internal combustion engine is shut off when the tank contains a certain residual quantity of fuel. Such a shutoff is prohibited by law in certain countries. If such a measure of shutting off the internal combustion engine when the tank contains a residual quantity is not provided, a fuel tank running on empty and thus penetration of air into the fuel metering system cannot be prevented.